BUG: When no tubes are extracted, SegmentTubes should EXIT_FAILURE
BUG: When no tubes are extracted, SegmentTubes should EXIT_FAILURE

thewtex/TubeTK,aylward/ITKTubeTK,KitwareMedical/TubeTK,thewtex/TubeTK,thewtex/TubeTK,aylward/ITKTubeTK,KitwareMedical/TubeTK,KitwareMedical/ITKTubeTK,aylward/ITKTubeTK,thewtex/TubeTK,KitwareMedical/ITKTubeTK,KitwareMedical/TubeTK,KitwareMedical/ITKTubeTK,aylward/ITKTubeTK,KitwareMedical/TubeTK,KitwareMedical/ITKTubeTK